Luminescent planar sheet

ABSTRACT

A vehicle lighting system is provided primarily for use with emergency response vehicles. The lighting system includes a planar plate mounted to one of the horizontal surfaces of a vehicle. A luminescent planar sheet is constructed to provide illuminated alphanumeric characters affixed upon the planar plate so as to be seen from the air. Preferably the luminescent planar sheet can selectively produce visible light, or light invisible to the human eye. Where the planar luminescent panel produces heat to create non-visible infrared indicia, it is preferred that the planar luminescent sheet include an insulator layer positioned under the infrared producing layer so as to prevent heat from dissipating into the vehicle&#39;s metal surface.

RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 14/512,171 filed on Oct. 10, 2014, which in turn is acontinuation-in-part application of co-pending U.S. patent applicationSer. No. 14/070,925 filed on Nov. 4, 2013, which in turn is acontinuation-in-part application of co-pending U.S. patent applicationSer. No. 13/385,697 filed on Mar. 2, 2012, now U.S. Pat. No. 8,585,263issued Nov. 19, 2013, which in turn is a continuation-in-partapplication of U.S. Patent Application Ser. No. 61/464,515 filed on Mar.4, 2011.

BACKGROUND OF THE INVENTION

The present invention relates to indicia that can be affixed on top ofthe horizontal planar surfaces of emergency response vehicles such asfire department vehicles, police cars and ambulances to providevisibility from above.

Most conventional emergency response vehicles provide audible alertwarnings and visual alert warnings such as sequenced flashing of head,tail and side light assemblies, or a roof mounted light bar containingat least one light source designed to disburse light in 360 degrees.These lights may be solid, stroboscopic, revolving, flashing, modulated,pulsing, oscillating, alternating, or any combination thereof. Thus,these light systems are designed primarily for viewing from the front,rear, or side of emergency response vehicles.

While in most situations, any of the aforementioned devices wouldsuffice in alerting a passerby of the presence of the emergency responsevehicle, there are crucial situations in which greater visibility isrequired. For example, in the case of vehicular pursuits, helicopterunits are often called for service to help ground units observe andtrack pursuits as well as ensure public safety while in pursuit.Helicopters provide valuable service to law enforcement in general and,more particularly, to the pursuit function. Helicopter units can assistground units as a platform from which to observe, track and illuminatepeople or places on the ground. Moreover, the helicopter units serve asbackup to ground units, and the helicopter flight crews can provide aperspective that cannot be achieved on the ground. Further, they cancommunicate with ground units and provide information to direct themtoward an intended position or away from a dangerous one. In addition,the helicopter units can provide crucial information, such as reportingwhether or not suspects are carrying weapons, etc.

There is a need for a system to assist helicopter units indistinguishing ground units and their positioning. Currently, manypolice vehicles already have numerals illustrated on top of their roofs.These numerals are used to differentiate a police vehicle from othervehicles and to help identify the police district, the unit, and theindividual. However, typically, these numerals are in plain black textand are not illuminated. Therefore, when there is little or no light, itcan be difficult to distinguish the numbers on top of a police vehicle.

Moreover, even if vehicles were provided with illuminated indicia, it isdifficult to maintain consistent illumination as letters and numbershave different surface areas, and thus would have different powerrequirements to provide consistent illumination.

Therefore, there is a need for better identification of emergencyresponse vehicles for being seen from above.

Furthermore, there is a need for improved power and switching systems toprovide 5 consistent illumination to illuminated indicia upon emergencyresponse vehicles.

SUMMARY OF THE INVENTION

The present invention is directed to an illuminating alphanumericlighting system for emergency response vehicles that is able to enhancethe visibility of emergency response vehicles to those in the air, suchas in helicopters.

The illuminated lighting system provides indicia, in the form ofilluminated letters or numerals, on the top of the substantially planarsurfaces of emergency response vehicles, such as upon the vehicle hoods,cabins and trunks. The size of the indicia may vary depending upon thepurpose of the lighting system, and the size of the horizontal surfaceupon which the indicia is placed. However, preferred letters andnumerals have a length greater than one (1) foot and a width greaterthan one-half (½) foot. More preferably, the letters and numbers have alength of one (1) to five (5) feet and a width of one-half (½) foot totwo (2) feet. Still more preferred, the letters and numbers have alength of approximately two (2) feet and a width of one (1) foot.

To provide illumination to the illuminated numerals and letters, poweris provided from the vehicle's electrical systems, such as from thevehicle's battery and alternator. The electrical wiring and switchingsystem for the luminescent panels can be developed by those skilled inthe art. However, in preferred embodiments the vehicle is provided witha conventional light bar that extends horizontally and laterally abovethe top of a vehicle. The light bar obtains power from the vehicle'selectrical system so as to emit light substantially horizontally,preferably 360 degrees. These lights may be solid, stroboscopic,revolving, flashing, modulated, pulsing, oscillating, and/oralternating. Preferably, additional wiring extends from light bar to theluminescent indicia so that the luminescent indicia obtains power fromthe light bar. Any AC/DC or DC/AC inverters, or voltage, amperage orwattage converters that supply appropriate power to the luminescentindicia may be located within the light bar housing. Furthermore, alighting system may include a light sensor for automatically disablingthe luminescent panels when daylight, or other ambient lighting, issufficiently strong so as to make the light produced by the luminescentindicia unnecessary. The light sensor may be a simple photocellconnected to the wiring connecting the power source to the luminescentindicia wherein the photocell automatically opens the electricalcircuit, or variably increases the electrical resistance, to inhibit thesupply of power to the luminescent indicia. The light sensor (photocell)may be located anywhere on the vehicle. However, in a preferredembodiment, the light sensor is mounted to the vehicle light bar.

The luminescent numerals and letters may be constructed in variousmanners. As a first example, the luminescent letters and numbers may bemade using a light pipe, also known as a light guide, connected to anindependent light source. The light source may be any of variousavailable lighting constructions known in the art. For example, thelight source may comprise one or more incandescent light bulbs, lightemitting diodes, light emitting crystals, etc. Moreover, the lightsource may produce light which can be selectively varied in color so asto enable the operator to alter the color of the luminescence. Forexample, the light source may comprise a plurality of diodes with eachdiode producing different colored light. Selective activation anddeactivation of the diodes alone or in combination will produceillumination in different colors.

The light guide may be constructed in various shapes and of variousmaterials such as of lengths of acrylic plastic, polycarbonate, or glassto form the desired letters or numerals for display from the top of avehicle. Alternatively, the light pipe may be constructed of one or morefiber optic fibers or cables. The light pipes may also be constructed ofone or more different translucent and fluorescent colored materials forprojecting light of one or more colors. An acceptable colored materialincludes “scintillating plastic” which is typically an acrylic plasticincorporating different colored fluorescent dyes. Preferably, the lightguide includes a reflecting bottom layer for directing light upwardly soas to be seen from above.

Where the light guide incorporates fiber optic cables, the fiber opticcables are also constructed to project light laterally from theircylindrical exterior as opposed to predominantly from their distalextremities. This can be accomplished by notching, knurling, scratchingor in other manners creating flaws in the otherwise smooth exteriorcylindrical surface of the fiber optic cable. These flaws have beenfound to interrupt the transmission of light along the length of thefiber optic cable and to transmit light laterally from the exteriorsurface of the fiber optic cable, typically opposite the side which hasbeen flawed.

In an additional preferred embodiment of the present invention, theluminescent letters and numbers are constructed of substantially planarelectroluminescent (EL) panels. A first EL construction is described inU.S. Pat. No. 5,045,755 issued to Appelberg and assigned to ELiteTechnologies, Inc. which is incorporated herein by reference. Theilluminating sheet is a split electrode or parallel plate lampconsisting of a main body sandwiched between first and second conductivelayers. Application of an alternating current to the planar sheetprovides a luminescent sheet which is formed in the shape of numeralsand letters.

An additional preferred electroluminescent panel for producing theluminescent letters and numbers can be obtained from MKS, Inc. locatedin Bridgeton, N.J., USA under the trademark designation Quantaflex™. TheQuantaflex™ material is an electroluminescent lamp including luminescentphosphors embedded in the dielectric medium of a capacitor constructedin the form of a sheet. Electrodes, including at least one translucentelectrode, form the top and bottom layers of the Quantaflex™ material.Upon application of an alternating current to the electrodes, thephosphors give off photons producing light in the visible spectrum oflight. An advantage of the Quantaflex™ material is that the phosphorscan be selectively encapsulated between the electrode layers of theluminescent sheet so as to selectively produce patterns of light emittedfrom the luminescent sheet.

In still additional preferred embodiments, the luminescent numbers andletters are constructed of one of the rapidly developing technologiesdirected to Organic Light Emitting Devices (OLED), Transparent OrganicLight Emitting Devices (TOLED), or Flexible Organic Light EmittingDevices (FOLED). Descriptions of these technologies are available tothose skilled in the art and need not be described in further detailherein.

In still an additional embodiment illustrated, the luminescent lettersand numerals are provided by a panel including dozens or hundreds ofrows and columns of LEDs or the like which can be selectably illuminatedto form a desired indicia. For this embodiment, it is preferred that theLEDs are connected by wires to a controllable switching system, which inturn is connected to a computer processor or the like. The computerprocessor, in turn, includes an input device such as a keyboard orcontrol panel to allow controlled independent illumination of selectedLEDs to form the desired indicia. Though more expensive and requiringmore complicated wiring and processing capabilities to selectappropriate illumination to display desired characters, this embodimentallows for the indicia to be rapidly changed as desired.

In a preferred embodiment, the LEDs may produce only infrared light notvisible to the human eye and thus only visible through imaging systemssuch as night vision goggles. Alternatively, infrared light (not visibleto the human eye) is produced by introducing a voltage through anelectrically resistant material, such as a silver or copper alloy, inthe form of the indicia. As but an example, a silver material may beprinted to form an elongate electrical circuit upon the substratematerial adjacent to the illuminated portion of the electroluminescentportion to provide an invisible light producing section adjacent to theelectroluminescent visible light producing section. These non-visiblelight producing embodiments are advantageous when visible light is notdesirable which might alert criminals that law enforcement personnel areapproaching, but such law enforcement personnel have imaging systemscapable of seeing the non-visible indicia of their comrades' vehicles.

Preferably, the planar luminescent panels in the form of letters andnumbers are protected by a protective coating in the form of a laminatesheet. Because the preferred luminescent letters and numerals producelight in both infrared and visible light spectrums, it is preferred thatthe protective coating allow most of these spectrums of light to pass.However, it is preferred that the protective coating block ultravioletlight which can be harmful to the various electronics such as LEDs orelectroluminescent panels. In a preferred embodiment, the protectivecoating blocks at least 60% of ultraviolet light below 350 nanometers,but allows at least 80% of both visible and infrared light above 450nanometers. An even more preferred protective coating blocks at least90% of ultraviolet light below 350 nanometers, but allows at least 85%of visible and infrared light above 500 nanometers.

In the event that the planar luminescent panel produces non-visibleinfrared indicia produced by heat, it is preferred that the planarluminescent sheet include an insulator layer positioned under theinfrared producing layer so as to prevent heat from dissipating into thevehicle's metal surface. In a preferred embodiment, the insulator layerincludes a pre-applied adhesive for applying the planar luminescentsheet(s) to a vehicle.

Preferably, a controller in the form of a switching system or computerprocessor is provided to allow operators to control the operation of theilluminated indicia. Even more preferably, the switching system canselectively strobe the illuminated indicia. In still an additionalembodiment, the switching system includes manual or automatic variableresistors for controlling the wattage provided to each illuminatedindicia so that the wattage may be varied between each illuminatedindicia.

Advantageously, the controller can selectively control the planar lightpanel to produce infrared light above 760 nanometers, while notproducing substantial visible light below 600 nanometers so as to besubstantially invisible to the human eye with the protective coatingallowing at least 80% transmission of the infrared light through theprotective coating. Still an additional advantage of the presentinvention is that the controller allows the planer light panel toproduce only visible light between 400 nanometers and 760 nanometers, orsimultaneously produce both visible light between 400 nanometers and 760nanometers and infrared light above 760 nanometers.

Advantageously, the luminescent numerals and letters may be adhereddirectly to the roof or top of an emergency response vehicle. However,in an alternative embodiment, a rectangular frame is provided foraffixing the luminescent panels to the top of the roof of emergencyresponse vehicles. In still an additional embodiment, a planar roofplate is provided which affixes to the vehicle manufacturer'spreexisting female threads formed into the roof of the vehicle which aretypically used for mounting a roof rack. Where the vehicle has acorrugated roof forming a plurality of troughs and ridges, preferablythe roof plate has a top surface that is substantially planar and abottom surface that includes a plurality of channels forming elongateteeth positioned and aligned to project into the vehicle's roof'stroughs. The roof plate engages and is affixed to the vehicle roof withthe roof plate's teeth extending into the vehicle roof trough so as toprovide better aerodynamics and to provide better support for itemsmounted to the plate's upper surface. Indicia, antenna, or light barsmay be mounted to the roof plate's top surface.

In a preferred embodiment, the planar roof plate has a top wallincluding the top surface, two sidewalls, a front wall and a rear wall.Small holes, ports or slots may be drilled or formed into the top wall,left and right sidewalls, or front and rear walls for the routing ofelectrical wiring. However, it is preferred that the two sidewalls,front wall and rear wall are sized and constructed to engage the vehicleroof substantially along their lengths to form a central cavity betweenthe vehicle roof and top wall. Where the vehicle roof is not corrugatedbut instead relatively smooth, it is preferred that the planar roofplate's front and rear walls also be relatively smooth to conform andengage the vehicle's top surface. However, where the vehicle has acorrugated roof forming a plurality of troughs and ridges, preferablythe roof plate front wall and/or rear wall includes channels formingelongate teeth positioned and aligned to project into the vehicle'sroof's troughs. It is preferred that any wiring to a light bar orluminescent indicia upon the roof plate be located in the central cavityfor the protection of the wiring and to reduce aerodynamic drag thatmight be produced by the wiring.

Once mounted directly to the roof of a vehicle or upon the planar roofplate, the illuminated numerals and letters are easily visible to thosein the air.

Thus, it is an additional object of the invention to provide a structurefor identifying emergency response vehicles from the air, such as bythose in planes and helicopters.

Further, it is an object of the present invention to provide an improvedvehicular external lighting system capable of operating with a lowcurrent draw and able to be simply integrated into an existing vehicle'selectrical system.

These and other more specific objects and advantages of the inventionwill be apparent to those skilled in the art from the following detaileddescription taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an emergency response vehicle equippedwith illuminated indicia affixed on top of the roof;

FIG. 2 is a top-exploded view of a frame possessing luminescent panelsof the present invention;

FIG. 3 is a top view of a frame possessing luminescent panels of thepresent invention;

FIG. 4 is a top view of a frame possessing luminescent panels of thepresent invention possessing LED's;

FIG. 5 is a front perspective view of the present invention;

FIG. 6 is a top elevation view of the present invention;

FIG. 7 is a top elevation view of an alternative embodiment of thepresent invention;

FIG. 8 is a perspective view of illuminated indicia in the form of anelectroluminescent panel;

FIG. 9 is a perspective view of illuminated indicia in the form of fourelectroluminescent panels for identifying an emergency response vehicle;

FIG. 10 is a top plan view of illuminated indicia in the form of fourelectroluminescent panels for identifying an emergency response vehicle;

FIG. 11 is a top perspective view of illuminated indicia in the form ofthree luminescent panels connected to a controller for activating andcontrolling the amount of wattage provided to electroluminescent indiciaand for activating and controlling the amount of wattage provided toinfrared/thermal indicia;

FIG. 12 is a perspective view of illuminated indicia in the form ofthree luminescent panels and a radio frequency antennae affixed to aplanar plate constructed to be mounted upon the corrugated roof of avehicle;

FIG. 13 is a top plan view of illuminated indicia in the form of threeluminescent panels affixed to a planar plate which in-turn is mountedupon the corrugated roof of a vehicle, and illustrating a controller foractivating and controlling the amount of wattage provided toelectroluminescent indicia and for activating and controlling the amountof wattage provided to infrared/thermal indicia;

FIG. 14 is a top plan view of the luminescent panels, planar plate,vehicle, and controller of FIG. 13 wherein the controller has activatedand adjusted the wattage provided to the electroluminescent indicia;

FIG. 15 is a top plan view of the luminescent panels, planar plate,vehicle, and controller of FIG. 13 wherein the controller has activatedand adjusted the wattage provided to the infrared/thermal indicia;

FIG. 16 is a top plan view of the luminescent panels, planar plate,vehicle, and controller of FIG. 13 wherein the controller has activatedand adjusted the wattage provided to the infrared/thermal indicia, andthe controller has activated and adjusted the wattage provided to theelectroluminescent indicia;

FIG. 17 is a simplified electrical diagram illustrating the switchingsystem including 20 adjustable variable resistors to adjust the wattageprovided to each infrared/thermal indicia and to each electroluminescentindicia;

FIG. 18 is a top, right, rear perspective view of a second embodiment ofthe vehicular roof plate;

FIG. 19 is a bottom, left, rear perspective view of the secondembodiment of the vehicle roof plate;

FIG. 20 is a top plan view of the second embodiment of the vehicle roofplate;

FIG. 21 is a bottom plan view of the second embodiment of the vehicleroof plate;

FIG. 22 is a top perspective view illustrating the second embodiment ofthe vehicular roof plate supporting emergency response vehicleidentification characters and affixed to the corrugated roof of avehicle;

FIG. 23 is a top, right, rear perspective view of a third embodiment ofthe vehicular roof plate;

FIG. 24 is a top, left, front perspective view of the third embodimentof the vehicle roof plate;

FIG. 25 is a top plan view of the third embodiment of the vehicle roofplate;

FIG. 26 is a bottom plan view of the third embodiment of the vehicleroof plate;

FIG. 27 is a top perspective view illustrating the third embodiment ofthe vehicular roof plate affixed to the corrugated roof of a vehicle andsupporting emergency response vehicle identification characters;

FIG. 28 is a top perspective view illustrating the second embodiment ofthe vehicular roof plate affixed to the corrugated roof of a vehicle andsupporting emergency response vehicle identification characters and alight bar; and

FIG. 29 is a top perspective view illustrating the third embodiment ofthe vehicular roof plate affixed to the corrugated roof of a vehicle andsupporting emergency response vehicle identification characters and alight bar.

DETAILED DESCRIPTION OF THE INVENTION

While the present invention is susceptible of embodiment in variousforms, as shown in the drawings, hereinafter will be described thepresently preferred embodiment of the invention with the understandingthat the present disclosure is to be considered as an exemplification ofthe invention, and it is not intended to limit the invention to thespecific embodiments illustrated.

With reference to FIGS. 1-29, the present invention is a vehicularilluminated sign 1. The vehicular illuminated sign comprises two primarycomponents including the vehicle 3 and luminescent planar sheet 7. Theterms “vehicle” and “luminescent planar sheet” are to be interpretedbroadly as to encompass a wide variety of embodiments as would beunderstood by those skilled in the art. For example, the vehicle 3 isany wheeled vehicle for travel upon the roads and highway of thiscountry including automobiles, trucks, vans, etc. The present inventionis intended primarily for emergency response vehicles. However, theinvention may have application for identifying trucking fleets and thelike. Each of these vehicles have substantially horizontal planarsurfaces 5, such as the hood, cabin top, and trunk illustrated in FIGS.6 and 7.

The luminescent planar sheet 7 of the present invention is mounted uponone or more of the vehicle's horizontal planar surfaces 5. Theluminescent planar sheet 7 is mounted substantially horizontally so asto display indicia 9 upwardly. The indicia 9 is in the form of one ormore alpha-numeric characters having a length (commonly referred to as aheight) and a width. The alpha-numeric characters are provided toidentify a vehicle, and thus are preferably unique to that vehicle. Thealpha-numeric characters may have any height or width as necessary so asto identify the vehicle from the air. However, the alpha-numericcharacters preferably have a length greater than 1 ft. and a widthgreater than ½ ft. Still more preferably, each of these numbers orletters forming the indicia has a length of approximately 2 ft. and awidth of 1 ft.

The luminescent planar sheets may be constructed to produce light invarious colors, and may switch between different colors. In still anadditional embodiment of the present invention, the luminescent planarsheet may be constructed to produce light which is primarily invisibleto the human eye such as in the infrared spectrum. The term “primarilyinvisible to the human eye” is intended to be interpreted broadlybecause traditional light sources producing light in the infraredspectrum, including heat producing systems, will often produce a minimalamount of light in the visible spectrum. However, as understood by thoseskilled in the art, such infrared/thermal light sources are highlyvisible when wearing night vision goggles or the like.

The luminescent planar sheet is connected to a power system mountedwithin the vehicle. The power system may be in the form of a batteryseparate from the vehicle's traditional battery mounted under the hood.However, preferably the illuminated vehicular sign utilizes the powersystem already provided in a vehicle including the battery andalternator. To control the power to the luminescent planar sheet 7,preferably one or more switches are positioned within the vehicle'scabin so as to control the on or off illumination of the sign. Further,switches may be provided to control the brightness of the illuminationand/or color being illuminated. For example, the signage may changecolors so as to indicate different events. For example, the luminescentplanar sheet may be made to illuminate red in the event of an emergency.Alternatively, the luminescent planar sheet may be made to strobe in theevent of an emergency. Switching systems for providing these featurescan be easily deduced by those skilled in the art and are not describedfurther herein.

As illustrated in FIGS. 2-10, the luminescent planar sheet may beconstructed in various manners. As illustrated in FIGS. 2 and 3, in afirst embodiment, the luminescent planar sheet comprises a light pipe 17and an independent light source in the form of fluorescent bulbs. Thelight pipe may be made to create opaque alpha-numeric characters withluminescent borders around the alpha-numeric characters. Alternatively,the luminescent planar sheet may be made to create luminescentalpha-numeric characters and an opaque border so as to identify suchcharacters. As illustrated in FIGS. 4 and 5, the luminescent planarsheet may comprise a plurality of LEDs forming the light source which isagain covered by a light pipe 17. Again, as illustrated in FIGS. 6 and7, the indicia may be made to illuminate with an opaque border.Alternatively, the illuminated planar sheet may be made to have opaqueindicia with an illuminated border. Where LEDs are employed, theswitches controlling activation of the LEDs may be controlled by acomputer processor as to form different indicia as desired.

In still an additional embodiment illustrated in FIGS. 8-10, theluminescent planar sheet 7 is constructed in the form of one or moreelectroluminescent (EL) panel lamps. The electroluminescent panels maybe constructed in various forms such as described in U.S. Pat. No.5,045,755. Alternatively, the electroluminescent panels may beconstructed of organic light emitting diodes or devices (OLED),transparent organic light emitting devices (TOLED), or flexible organiclight emitting devices (FOLED).

Advantageously, where the luminescent planar sheet 7 is constructed inthe form of an EL panel 9, the EL panel can be adhered directly to oneof the vehicle's horizontal planar surface 5. Conversely, where theluminescent planar sheet 7 is constructed to include LEDs or light bulbs21, the luminescent planar sheet 7 will typically require a frame 15 forholding the light source, as illustrated in FIGS. 2-5. As illustrated inFIG. 10, preferably any wires 58 for supplying power to the luminescentplanar sheet can be routed to a vehicle's existing light bar 27.

In a preferred embodiment, the lighting system may include a lightsensor for automatically disabling the luminescent planar sheets whendaylight, or other ambient lighting, is sufficiently strong so as tomake the light produced by the luminescent indicia unnecessary. Thelight sensor may be a simple photocell, such as photo-resistor, inseries with the wiring which connects the power source to theluminescent indicia. The light sensor automatically opens the electricalcircuit, or variably increases the electrical resistance, to inhibit thesupply of power to the luminescent indicia. The light sensor (photocell)may be located anywhere on the vehicle. However, as illustrated in FIGS.10 and 28, in a preferred embodiment, the light sensor 80 is mounted orotherwise incorporated into the vehicle light bar. Advantageously, thelight sensor 80 will prevent the unnecessary use of the luminescentplanar sheets during daylight which would unnecessarily utilize batterypower and shorten the life of the light source(s).

As illustrated in FIGS. 11-17, in the currently preferred constructionof the vehicular lighting system, each luminescent indicia 9 isconstructed to include a central electroluminescent portion 40 poweredby a first electrical circuit and a thermal/infrared portion 42 poweredby a second electrical circuit. Preferably, the thermal/infrared portionis simply a highly resistant material, such as a silver or copper alloy,in the form of the indicia. As illustrated, the silver material 42 maybe printed to form an elongate circuit upon the substrate materialadjacent to the illuminated portion of the electroluminescent portion40. In operation, a voltage is applied to the resistant material 42causing the thermal/infrared portion to be heated to formthermal/infrared indicia.

With reference to FIGS. 8 and 9, where the infrared indicia is producedby heat, it is preferred that the planar luminescent sheet 7 include aninsulator layer 43 positioned under the electroluminescent 40 andinfrared 42 producing layer so as to prevent heat from dissipating intothe vehicle's metal surface. In a preferred embodiment, the insulatorlayer 43 includes a pre-applied adhesive 45 for applying the planarluminescent sheet(s) 7 to a vehicle. Preferably, the adhesive 45 iscovered by a peel away sheet (not shown) which can be easily peeled awayby the installer when applying the planar luminescent sheet to avehicle. Meanwhile, in a preferred embodiment, the bottom surface of theelectroluminescent 40 and infrared 42 producing layer includes anadhesive for affixing to the top surface of the insulator layer 43.

In preferred embodiments, the insulator layer 43 has a thickness of atleast 0.075 mm, a thermal conductivity of 0.25 W/m-K or less, and athermal resistance “R-value” of 0.00050 m²K/W or greater, and wherein“mm” refers to millimeters, “m” refers to meters, “W” refers to watts,and “K” refers to Kelvin. More preferably, the insulator layer 45 has athickness of at least 0.080 mm and a thermal conductivity of 0.20 W/m-Kor less. In still an additional preferred embodiment, the insulatorlayer 43 incorporates an adhesive 45 for affixing the insulator layer toan object such as a vehicle's planar surface. Preferably, this insulator43 with adhesive 45 has thickness of at least 0.100 mm and a thermalconductivity of 0.18 W/m-K or less. A preferred insulator material thatcomplies with these requirements is sold by 3M Company under their partnumber IJ35 which, with adhesive, has a thickness of 0.102 mm, anapproximate thermal conductivity of 0.18 W/m-K, and an approximatethermal resistance R-value of 0.00055 m²K/W as tested in accordance withASTM E1530 Rev. 11.

A preferred illuminated vehicle sign of the present invention utilizeselectroluminescent indicia 40 operating at 14.4 volts and 800 Hz. Toprovide these power characteristics, preferably an inverter (not shown)converts the vehicle's DC 12 volts to a nominal 14.4 volts and 800 Hz.However, alphanumeric characters of the same font size have differentsurface areas. For example, preferred electroluminescent numbers havingthe same 20 inch height have the following respective surface areas:

Number Square Inches 0 117 1 68 2 110 3 98 4 107 5 113 6 110 7 78 8 1219 110

It has been discovered that providing each of the numerals with the samewattage results in some numbers being brighter than others. Similarly,if the same wattage is provided to each thermal/infrared portion of theluminescent indicia, this will result in some indicia having a muchgreater temperature than other indicia or will result in alphanumericcharacters with lesser surface areas “burning” out quicker than others.Moreover, it is common to substitute the alphanumeric characters atopemergency response vehicles.

To overcome these problems, as illustrated in FIGS. 11-17, the switchingsystem 50 of the present invention includes adjustable variableresistors 64 and 74 which adjust the current, and accordingly, thewattage provided to the electroluminescent portion and/orthermal/infrared portion of the indicia to provide uniform luminescence.In one embodiment of the invention, the adjustable variable resistors 64and 74 are controlled automatically based upon automated determinationsof the size of each indicia. To this end, preferably the switchingsystem includes one or more resistance, current, voltage, or wattagesensors for measuring the resistance, current, voltage or wattage of theelectroluminescent portion and/or thermal/infrared portion of theluminescent planar sheets, and includes a controller for automaticallyadjusting the resistance of the adjustable variable resistors 64 and 74based upon measurements made by these sensors. The circuitry forproviding this automatic adjustment of the adjustable variable resistors64 and 74 can be determined by those skilled in the art without undueexperimentation.

In an alternative embodiment of the invention illustrated in FIGS.11-17, the switching system 50 includes manually controlled variableresistors 64 and 74. Preferably, the switching system 50 includes on/offswitches 62 and 72 for activating and deactivating either theelectroluminescent portions and/or the thermal/infrared portions 42, andincludes manually rotatable switches 64 and 74 for varying theresistance, and thus wattage provided to the electroluminescent portionsand/or the thermal/infrared portions 42. Though illustrated in FIGS.11-17 as in one control box, it is preferred that the on/off switches 62and 72 be located within the vehicle cabin so as to be easily accessibleto emergency response personnel, and it is preferred that the manuallyrotatable switches 64 and 74 be located so as to be accessible onlyduring installation of vehicular illuminated sign 1 so as to not beinadvertently altered after installation.

In still an additional embodiment, the luminescent panels include one ormore resistors (not shown) located within each of the luminescent panelsto provide uniform electrical characteristics across the spectrum ofdifferent alphanumeric characters. More specifically, for thisembodiment, the luminescent indicia are constructed to include resistorselectrically connected to the electroluminescent circuitry and/or thethermal/infrared circuitry so that alphanumeric characters of differentsurface areas can be swapped but still provide uniform luminescence.

With reference to FIGS. 3, 8 and 9, preferably the top surfaces of theluminescent panels include a protective coating 41. Because theluminescent panels of the present invention preferably produce light inthe visible light spectrum and/or infrared spectrum, it is preferredthat the protective coating is substantially translucent within thesespectrums of light. However, it is preferred that the protective coatingblocks most or substantially all light in the ultraviolet (UV) lightspectrum.

The protective coating 41 will provide protection against abrasion andvarious forms of environmental radiation. The protective coating maytake various forms. For example, the protective coating may beincorporated in the manufacturing process utilizing a spray coating.However, a laminate application is preferred. Where the luminescentpanel is an electroluminescent panel, it is preferred that theprotective coating forms the upper layer of the electroluminescent paneland is preferably a flexible plastic. Moreover, it is preferred that theprotective coating blocks at least 60% of ultraviolet light below 350nanometers, and even more preferably blocks at least 90% of ultravioletlight below 350 nanometers. Conversely, it is preferred that theprotective coating allow at least 80% transmission of visible infraredlight above 450 nanometers, and even more preferably allow at least 85%of visible and infrared light above 500 nanometers. Furthermore, it ispreferred that the protective coating have an adhesive 45 (seen in FIG.8) formed on its bottom surface for applying the protective coating 41to the top surface of the luminescent planar sheets 7. Acceptableprotective coatings providing these characteristics include polyvinylfluoride (PVF) films, polymethyl methacrylate films, Tedlar from Dupont,and Acrylar from 3M Company.

Advantageously, the luminescent panels of the present invention arecontrolled by the control processor so as to illuminate in only thevisible spectrum of light, or in only the invisible infrared spectrum oflight, or simultaneously in both the visible and infrared lightspectrums. Furthermore, and advantageously, the protective coatingpermits the passage of most of the visible light and infrared lightproduced by the luminescent panel, while blocking most of theultraviolet light. Accordingly, the luminescent panel of the presentinvention is capable of producing visible light between 400 nanometersand 760 nanometers, or producing infrared light above 760 nanometerswhile not producing appreciable visible light below 760 nanometers, orproducing both visible light, and infrared light.

Currently, non-illuminated indicia are adhered directly to the roof andtrunk areas of emergency response vehicles. Similarly, the luminescentplanar panels may be affixed to the vehicle's horizontal surfaces usingadhesives or the like. Alternatively, the luminescent planar panels areaffixed to a supplemental structure mounted on the vehicle. In apreferred embodiment, the vehicle is constructed to support atraditional roof rack, and to this end, the vehicle also includes fouror more threaded bolt holes installed by the original manufacturer ofthe vehicle. If installed, the traditional roof rack of horizontallyextending bars is removed. Instead, with reference to FIGS. 11-12, thevehicle is equipped with a planar plate 30 which includes flanges 35that extend downwardly to mount to the vehicle bolt holes. Bolts, orother threaded fasteners, are employed to affix the planar plate 30 inplace. Where the vehicle roof includes a plurality of longitudinaltroughs, the bolt holes may be located in such troughs. For thisconstruction, the planar plate is preferably constructed to includeelongate flanges 35 along its left and right edges that will projectinto the troughs where vehicle threaded bolt holes are located. Theflanges 35 include holes for receiving male fasteners which mount to thevehicle bolt holes.

With reference to FIGS. 18-22, in a preferred embodiment, the planarroof plate 30 has a top wall 31 including the top surface, two sidewalls35 in the form of downwardly extending flanges, a front wall 33 and arear wall 34. Small holes, ports or slots 32 may be drilled or formedinto the top wall 31, left and right sidewalls 35, or front 33 and rearwalls 34 for the routing of electrical wiring. However, it is preferredthat the two sidewalls 35, front wall 33 and rear wall 34 are sized andconstructed to engage the vehicle roof 4 substantially along theirlengths to form a central cavity 51 between the vehicle roof 4 and topwall 31. It is preferred that any wiring to the light bar 27 orluminescent indicia upon the roof plate be located in the central cavity51. Preferably, a single hole (not shown) is formed into the vehicleroof under the roof plate 30 to permit the routing of all wiring fromthe vehicle switching system and power supply to the light bar 27,luminescent indicia 9 and antennae 44. It is preferred that the cavity51 be sufficiently high, at least one-eighth (⅛) inch and morepreferably at least one-quarter (¼) inch, so as to allow the routing oftraditional low voltage electrical cables. However, it is preferred thatthe height of the cavity 51 be minimal, less that two (2) inches andmore preferably less than one (1) inch, to minimize the overall heightof the planar roof plate 30.

In a preferred embodiment not shown in the figures, where the vehicleroof is not corrugated but instead relatively smooth, it is preferredthat the planar roof plate's front and rear walls also be relativelysmooth to conform and engage the vehicle's top surface. Unfortunately,vehicles having corrugated roofs result in the alphanumeric charactersbeing warped when adhered to such roofs and difficult to read fromabove, such as by those in helicopters. As illustrated in FIGS. 18-27,in preferred embodiments, preferred roof plates 30 are specificallyconstructed to engage and conform to the corrugated features of avehicle roof Specifically, a vehicle's corrugated roof 4 includesrecessed troughs 38 formed by projecting ridges 39. The troughs andridges extend longitudinally from the front to the back upon a vehicle'sroof and are provided to provide greater stiffness and support. Forthese embodiments, the planar plate's bottom surface, or front and rearwalls, are not wholly planar. Instead, the planar plate's bottom surfaceor front and rear walls include a plurality of “teeth” 37 sized forprojecting into the vehicle roofs troughs 38. The plate teeth 37 formchannels 36 for receiving a vehicle roofs ridges 39.

As illustrated in FIGS. 18-22, a vehicle's corrugated roof may berelatively uniform from front to back providing troughs and ridges whichextend longitudinally having the same width and depth where the roofplate 30 is intended to be mounted upon the vehicle roof 4. Accordingly,as illustrated in FIG. 19, for this embodiment the roof plate's channels36 and teeth 37 are of approximately the same size at the roof plate'sfront as at the roof plate's rear. The roof plate's channels 36 andteeth 37 may extend longitudinally the entire length of the roof platefrom front to back. Alternatively, as best illustrated in FIG. 19, theroof plate channels 36 and teeth 37 may be located only at the roofplate's front and rear edges so as to provide improved aerodynamics andsupport for the planar plate 30 upon the corrugated roof 4 of a vehicle3. However, not all vehicles have vehicle troughs and ridges whichextend with uniform width and depth. For example, as illustrated inFIGS. 23-29, the planar plate 30 may include a front or rear wall(illustrated as the rear wall 34) which includes a bottom surface formedto include channels 36 and teeth 37 for conforming with the corrugatedroofs troughs 38 and ridges 39. However, towards the opposite edge ofthe roof plate, the vehicle's roof may not be corrugated. Accordingly,the planar plate 30 of this embodiment has an opposite edge (illustratedas the front wall 33) which does not include a plurality of teeth andchannels.

The planar plate 30 may be constructed of various materials andmanufactured by various methods as can be determined by those skilled inthe art. For example, the planar plate illustrated in FIGS. 18-22 ispreferably made of a durable plastic such as polyethylene, polystyrene,or acrylonitrile butadiene styrene which is machine or molded. Analternative preferred roof plate illustrated in FIGS. 23-27 is made ofmetal such as steel, aluminum or titanium and is stamped to form theplate's front wall and rear wall channels 36 and teeth 37.

As illustrated in FIGS. 11-16, the planar plate is preferablyrectangular. However, the planar plate may incorporate subtle curves forimproved aerodynamics or aesthetics. Furthermore, as illustrated inFIGS. 18-27, the planar plate 30 may include a notch or hole 32 forpermitting the passage of a radio frequency antennae 44 typicallymounted upon the roofs 4 of emergency response vehicles 3. Furthermore,as illustrated in FIGS. 28 and 29, the light bar 27 may also be mountedto the planar plate 30 to reduce or eliminate holes drilled into thevehicle after leaving the original manufacturer. For this embodiment, itis preferred that the system include electrical wiring 58 that connectsthe light bar 27 to the luminescent indicia 9.

While several particular forms of the invention have been illustratedand described, it will be apparent that various modifications can bemade without departing from the spirit and scope of the invention.Accordingly, it is not intended that the invention be limited except bythe following claims.

I claim:
 1. An illuminated sheet comprising: a luminescent planar sheethaving a bottom side and a top side producing luminescent indicia in theinfrared spectrum, said luminescent indicia producing heat; and aninsulator layer affixed to said luminescent planar sheet's bottom side,said insulator sheet having a thickness of at least 0.075 mm and athermal conductivity of 0.25 W/m-K or less.
 2. The illuminated sheet ofclaim 1 wherein said insulator layer has thickness of at least 0.080 mmand a thermal conductivity of 0.20 W/m-K or less.
 3. The illuminatedsheet of claim 1 wherein said insulator layer has a thermal resistance Rvalue of 0.00050 m²K/W or greater.
 4. The illuminated sheet of claim 1wherein said insulator layer includes a top surface affixed to saidluminescent planar sheet's bottom side and a bottom surface including anadhesive for affixing the illuminated sheet to an object, and saidinsulator layer including adhesive has a thickness of 0.100 mm orgreater.
 5. The illuminated sheet of claim 1 wherein said luminescentplanar sheet includes a printed elongate circuit of electricallyresistant material that produces heat upon application of an electricvoltage to produce said luminescent indicia.
 6. The illuminated sheet ofclaim 3 wherein said luminescent planar sheet includes a printedelongate circuit of electrically resistant material that produces heatupon application of an electric voltage to produce said luminescentindicia.
 7. An illuminated sheet comprising: a luminescent planar sheethaving a bottom side and a top side producing luminescent indicia in theinfrared spectrum, said luminescent indicia produced by a printedelongate circuit of electrically resistant material that produces heatand infrared light upon application of an electric voltage; and aninsulator layer affixed to said luminescent planar sheet's bottom side,said insulator sheet having a thickness of at least 0.075 mm and athermal conductivity of 0.25 W/m-K or less.
 8. The illuminated sheet ofclaim 7 wherein said insulator layer has a thermal resistance R value of0.00050 m²K/W or greater.
 9. A vehicle and illuminated vehicular signcombination comprising: a mobile vehicle having a substantially planarsurface; a luminescent planar sheet luminescent planar sheet having abottom side and a top side producing luminescent indicia in the infraredspectrum, said luminescent indicia producing heat; and an insulatorlayer affixed to said luminescent planar sheet's bottom side foraffixing said luminescent planar sheet to said vehicle's substantiallyplanar surface, said insulator sheet having a thickness of at least0.075 mm and a thermal conductivity of 0.25 W/m-K or less; and a powersource for providing power to said luminescent planar sheet.
 10. Theilluminated sheet of claim 1 wherein said insulator layer has thicknessof at least 0.080 mm and a thermal conductivity of 0.20 W/m-K or less.11. The illuminated sheet of claim 9 wherein said insulator layerincludes a top surface affixed to said luminescent planar sheet's bottomside and a bottom surface including an adhesive for affixing theilluminated sheet to an object, and said insulator layer includingadhesive has a thickness of 0.100 mm or greater.
 12. The illuminatedsheet of claim 9 wherein said insulator layer has a thermal resistance Rvalue of 0.00050 m²K/W or greater.
 13. The illuminated sheet of claim 9wherein said luminescent planar sheet includes a printed elongatecircuit of electrically resistant material that produces heat uponapplication of an electric voltage to produce said luminescent indicia.14. The illuminated sheet of claim 12 wherein said luminescent planarsheet includes a printed elongate circuit of electrically resistantmaterial that produces heat upon application of an electric voltage toproduce said luminescent indicia.